Interesting, thanks for the context. I don’t know anything about asphalt, but if it didn’t cause any health or safety issues I’d place it on the innovation end of the spectrum. I’d be interested in things like how the spent diesel fuel was disposed of and if any petro chems would leach into stormwater from asphalt made this way.
The water characteristics you’re worried about sound like aesthetic problems, which might be displeasing but pose no real health risks. These vary significantly between public water systems. If the system pulls from surface water, the water might need more treatment in the dry season since contaminants concentrate in surface waters more that time of year. I’m lucky to live somewhere that has no noticeable taste/odor/color issues. For places that do, you should be able to drink it from tap without issue, but it might taste/smell better if you run it through a filter or even just let it sit in a pitcher in the fridge.
If a municipality were to cut corners with their water treatment in a similar way to the asphalt plant you mentioned (which sounds kinda shady btw), people would get sick and potentially die. Most municipalities are very risk averse and take liability seriously to avoid litigation/losing money. So, it’s not impossible, but I think it’d be unlikely for a city to skimp on water treatment just to save a few bucks. Water treatment facilities are also required to constantly test for things like pH, turbidity, and chlorine residual and report to the state, so it’s not as simple as hiding things from an inspector the day of.
I agree with Chapo. Maybe you can teach these things in addition to what your kid learns at school? Might be a fun way to spend time together anyway.